The present invention is directed to attaching a slider to a head suspension. More specifically, the present invention pertains to reducing the amount of adhesive needed to couple the slider to the head suspension.
FIG. 1 illustrates a hard disk drive design typical in the art. Hard disk drives 100 are common information storage devices consisting essentially of a series of rotatable disks 104 that are accessed by magnetic reading and writing elements. These data transferring elements, commonly known as transducers, are typically carried by and embedded in a slider body 110. The slider 110 is held in a close relative position by a head gimbal assembly (HGA), including a suspension 102 attached to an actuator arm 106, over discrete data tracks formed on a disk to permit a read or write operation to be carried out. The HGA is rotated around a pivot 108 by a voice coil motor 112. In order to properly position the transducer with respect to the disk surface, an air bearing surface (ABS) formed on the slider body 110 experiences a fluid air now that provides sufficient lift force to “fly” the slider 110 (and transducer) above the disk data tracks. The high speed rotation of a magnetic disk 104 generates a stream of air flow or wind along its surface in a direction substantially parallel to the tangential velocity of the disk. The air flow cooperates with the ABS of the slider body 110 which enables the slider to fly above the spinning disk. In effect, the suspended slider 110 is physically separated from the disk surface 104 through this self-actuating air bearing. The ABS of a slider 110 is generally configured on the slider surface facing the rotating disk 104 (see below), and greatly influences its ability to fly over the disk under various conditions.
FIGS. 2a-d illustrates a prior art method for coupling a slider 110 and micro-actuator 202 to the suspension 102 of an actuator arm 104. As shown in FIG. 2a, a slider 110 is coupled to a micro-actuator 202. The micro-actuator 202 provides a finer degree of slider movement control than the actuator arm 104. The micro-actuator 202 has a base 204 with two arms 206 projecting from the base 204. A stripe of piezoelectric (PZT) material 208 is coupled to the side of each actuator arm 206. An electric charge applied to the PZT stripe 208 causes it to expand or contract, moving the actuator arms 206. The slider 110 is bonded to the actuator arms 206 at the bonding points 210.
As shown in FIG. 2b, the micro-actuator 202 is couple to the suspension 102 via a suspension tongue 212. The suspension 102 is coupled to a base plate 214. The base plate has a hole 216 that allows the base plate 214 to rotate around a pivot. A series of traces 218 run the length of the suspension 102 and suspension tongue 212 to be electrically coupled to the slider 110 and the micro-actuator 202. The traces 218 are electrically coupled to a control circuit via a series of bonding pads 220 mounted on the base plate 214. As shown in FIG. 2c, the micro-actuator 202 is positioned so as to maintain a gap 222 between it and the suspension tongue 212 and by extension between the slider 110 and the suspension tongue 212.
The resonance performance of the suspension is a major factor in the resonance control of the HGA. The resonance performance is optimized during the manufacturing process in order to improve resonance control. The traditional method for testing the resonance performance of the suspension is to use a mechanical HGA. As shown in FIG. 2d, an actual slider 110 is fully potted to the suspension tongue 212 to create a mechanical HGA. The mechanical HGA is loaded into a resonance tester. The resonance tester can use a laser Doppler to monitor or sample the frequency response during mechanical shaking of the HGA base plate. Corrections can be made to the manufacturing process or the design based on the results of the test. The slider in this instance is easily recycled after testing is completed.
This testing method becomes more difficult for an HGA that includes a micro-actuator. Mounting the micro-actuator in addition to the slider requires a much more accurate mounting machine or fixture, mainly to maintain a parallel gap between the micro-actuator and the suspension tongue. Additionally, the micro-actuator is not so easily used and recycled as the micro-actuator is fragile and its manufacture is difficult and expensive.